Integral vehicle body frames exhibit at least two upper side frame rails of a front end, which are to be structurally joined at the front to a passenger cabin of the body, adjoining a side panel structure. The frame rails can here be secured directly to an A-column or a hinge pillar adjoining the latter from below.
In order to provide a wheel housing for the front wheels, the frame rail section located upstream from the bulkhead is vertically offset relative to an upper frame rail or wheel suspension strut that extends from the hinge pillar in the longitudinal direction of the vehicle opposite the traveling direction and lies in the area of the passenger cabin. In particular, to absorb and transfer the mechanical loads and forces that arise, for example during a collision, the connection between frontal frame rail segments, i.e., those located in front of the bulkhead, and the side panel structure must satisfy prescribed load requirements. Of course, correspondingly thick-walled steel plates can be used to provide sufficiently stable structural connections in the motor vehicle body construction.
However, in order to reduce fuel consumption and improve the CO2 balance of motor vehicles associated therewith, it is desirable to improve the vehicle weight while retaining, if not even improving, the mechanical load limits, for example with respect to the torsional rigidity and stability of a motor vehicle body. In addition, there is a constant requirement to improve the structural behavior of the motor vehicle body in terms of passenger and pedestrian protection, as well as with respect to durability.
For example, DE 43 29 050 C2 discloses a body in white, in which a respective hinge pillar comprising the lower portion of an A-column is connected with a frame rail that runs toward the front from the hinge pillar and is labeled as a wheel suspension strut. The wheel suspension strut is here welded via weld faces to a bulkhead side panel that forms a wheel housing and a door opening frame that comprises the outer skin of the motor vehicle.
While the individual components are here usually welded and bonded together via spot welding, corresponding holes must be furnished in the wheel suspension strut for this purpose, so that access can be provided to the underlying components by means of a welding tool. The disadvantage here on the one hand is that a portion of the wheel suspension strut covered by the side panel must be sealed off. Since a corresponding seal weld extends along the entire weld face, it is relatively long. On the other hand, this weld seam must be checked and examined for tightness before welding on an outer wheel suspension strut, since even just a regionally leaky weld seam might allow water into the hinge pillar, and hence into the vehicle interior, over the long-term operation of the vehicle.
In addition, an opening in the wheel suspension strut or frame rail to be provided for access with the welding tool weakens the structure of such bearing structure components. Instead of spot-welding, it is basically conceivable to connect the outer wheel suspension struts with the side panel structure or reinforcement of a hinge pillar situated under the latter, for example via gas-shielded welding, or via MIG or Mag welding, in particular in a CO2-welding process. However, the heat generated during such a welding process would damage a zinc coating of the bearing structure components, for example, thereby increasing the risk of corrosion precisely in the vicinity of the weld seam in some instances.
Therefore, at least one object is to provide an improved bearing structure arrangement in the transitional area between the front frame rail and a side panel structure lying in the vicinity of the bulkhead. The bearing structure arrangement is here to be characterized by a streamlined manufacturing process as well as an improved stability and torsional rigidity. It is here further provided that the wheel suspension struts or front frame rail section be secured to bearing structure components adjoining them via spot welding, but without having to furnish individual openings in the frame rail section for the welding process. In addition, other objects, desirable features and characteristics will become apparent from the subsequent summary and detailed description, and the appended claims, taken in conjunction with the accompanying drawings and this background.